Previous studies suggested differences in the abundance of IgG subclasses in anti-SARS-CoV-2 humoral responses after infection or vaccination, and it would have been interesting to quantify the relative contribution of IgG1, IgG2, IgG3, and IgG4 subclasses in our patient cohorts; however, this was not possible due to serum sample limitations (28, 65). This evidence concerns the gene IGHG3 and infection.